Coronavirus outbreak: everything you need to know

Public health experts around the globe are scrambling to understand, track, and contain a virus that appeared in Wuhan, China, at the beginning of December 2019. The World Health Organization (WHO) named the disease caused by the virus COVID-19, which references the type of virus and the year it emerged. The WHO declared that the virus is a pandemic.

The Verge will update this page as new information emerges. You can also find our breakdown of what research shows about how to live in a pandemic world here.

You can see where and how many cases of the illness have been reported on this map. As this important story continues to unfold, our hope is to keep you up to date as people work to understand this virus and contain its spread.

Table of contents

Where did the virus come from?

At the end of December, public health officials from China informed the World Health Organization that they had a problem: an unknown, new virus was causing pneumonia-like illness in the city of Wuhan. They quickly determined that it was a coronavirus and that it was rapidly spreading through and outside of Wuhan.

Photo by Kevin Frayer / Getty Images

Coronaviruses are common in animals of all kinds, and they sometimes can evolve into forms that can infect humans. Since the start of the century, two other coronaviruses have jumped to humans, causing the SARS outbreak in 2002 and the MERS outbreak in 2012.

Scientists think this new virus first became capable of jumping to humans at the beginning of December. It originally seemed like the virus first infected people at a seafood market in Wuhan and spread from there. But one analysis of early cases of the illness, published on January 24th, found that the first patient to get sick did not have any contact with the market. Experts are still trying to trace the outbreak back to its source.

The type of animal the virus originated from is not clear, although one analysis found that the genetic sequence of the new virus is 96 percent identical to one coronavirus found in bats. Both SARS and MERS originated in bats.

Where is it spreading?

The virus is now spreading all over the world.

Although it originated in China, the country took aggressive action at the start of the outbreak, shutting down transportation in some cities and suspending public gatherings. Officials isolated sick people and aggressively tracked their contacts, and had a dedicated network of hospitals to test for the virus.

Countries like New Zealand, Japan, and South Korea have successfully slowed the pandemic. The US has not, and it is an epicenter of the crisis.

How dangerous is this new virus?

It takes information about both how severe an illness is and how easily it can spread to determine how “bad” it can be. Epidemiologists often use this tool to assess new strains of the flu, for example:

Image: Centers for Disease Control and Prevention

If an illness isn’t very severe (and kills only a small percentage of people), but it’s highly transmissible, it can still be…